Wine is the fermented juice of grapes, although the term is also commonly used in conjunction with other fruits of the earth, such as barley wine, apple wine and ginger wine, for example. Fermentation of grapes is a natural phenomenon due to the catalytic action of the zymase of living microorganisms or ferments known as Saccharomycetes which are present on the skins of ripe grapes. Saccharomycetes are the natural yeast that make it possible for grape sugar (C.sub.6 H.sub.12 O.sub.6) to ferment into carbon dioxide (CO.sub.2) and ethyl alcohol (C.sub.2 H.sub.6 O). There are various by-products of fermentation which vary according to the chemical composition of the must, and in accordance with the rate and manner of fermentation. These by-products either dissolve in the wine or precipitate as sediments.
Wine is generally fermented in vats or barrels before bottling in consumer bottles. Sparkling wines and similar beverages are generally produced by methods which may be divided into two principal groups The classical method is carried out by bottling wine before the fermentation has been completed and allowing the wine to finish fermentation, or to undergo a second fermentation, in the bottle. By this method champagne or a similar beverage of highest quality is produced but the method is extremely troublesome and highly expensive. During fermentation in the bottle, grape sugar and/or sugar added to the wine is converted into alcohol and carbon dioxide, and the presence of the latter causes a relatively high pressure, for example, up to 12 atmospheres and greater, to be built up in the hermetically closed bottle. A danger of explosion constitutes a very serious problem in handling these bottles.
Besides the alcohol and CO.sub.2 production, sediments are also produced during fermentation in the bottle, and these must be removed before the champagne or other beverage may be sold and consumed. The removal of these sediments constitutes a major problem. Generally the bottles must be periodically shaken in order to prevent the sediments from adhering to the inner walls of the bottle. During shaking, the danger of explosions is particularly great and skilled labor has to be employed in order that the operation be properly executed. In order to remove the sediments from the bottle they are first collected upon the inside face of the cork of the bottle, whereafter the liquid in the neck of the bottle is frozen into solid state and finally the cork and the small block of ice containing the sediments are blown off with the aid of the gas pressure within the bottle. In order to avoid loss of liquid, immediately after removal of the sediments, the bottle must be hermetically closed again. In this step, as in the previous ones, great skill is required and, apart from the accidents that are liable to happen, losses of valuable liquid cannot be avoided in the period between the uncorking and the new sealing of the bottles. Typically liqueur, brandy and/or sugar are added to the wine to compensate for the wine lost during the removal of the frozen matter.
In order to overcome the aforementioned difficulties, many manufacturers of sparkling wines developed another method of producing such beverages. In this method, the wine concludes fermentation or undergoes a second fermentation not in bottles but in large sealed vats or containers. However, this method produces inferior quality beverages, and still does not solve the problem of removing dregs without removing the CO.sub.2 gas which contributes to the taste and bouquet of the wine. Indeed, collection and removal of sediments still poses a problem, even in the production of lesser quality effervescent beverages, such as "industrial" quality wines that are produced in bulk and continuous flow tanks. Filtering of the sediments is costly and there are generally detrimental effects to the taste and bouquet of the wine.
Manufacturers over the years have tried different filtration methods to discard the dregs while retaining sufficient CO.sub.2 needed to impart a desired level of effervescence. Some filtration methods, used especially for bottle-fermented wines, include placing a porous filter bag containing yeast into the wine. Dregs produced by the yeast-induced fermentation of the wine are generally confined in the yeast-holding filter bag, and are prevented from circulating in the wine. However, these filtration methods suffer from several problems. One problem with filter bags is that they prevent the `confined` yeast from circulating in the wine, and thereby limit the fermentation volumetric zone and lengthen fermentation time. Another problem faced by some filter-bag methods is that it is difficult to prevent the dregs from stopping up the pores of the bag, thereby retarding or adversely affecting the fermentation. Moreover, the taste of the wine may be adversely affected by the containment of the beneficial by-products of the fermentation inside the filter bag. Other problems, inter alia, include insufficient circulation of the yeast in the quantity of wine being fermented, a risk of breakage of the filter bag, continual need to remove the filter bag, and, as mentioned previously, the need to add materials to make up for losses occured during pressure release, and to restop the bottle.
The following United States Patents are believed to be representative of the prior art: U.S. Pat. Nos. 463,421 to Gerbel, 2,610,123 to Bruyere et al., 3,062,656 to Agablianz et al., 3,112,201 to Saez, 3,545,978 to Agabliants (sic) et al., 3,867,550 to Taylor, 3,875,008 to Yoshino et al., 3,881,021 to Merzhanian et al., 3,944,104 to Watson et al., 4,009,285 to Spooner, 4,076,142 to Naz, 4,265,914 to Sarashvili et al., 4,460,608 to Charmat, 4,612,949 to Konischev et al., 4,650,083 to Lembeck, 4,792,454 to Lemonnier, 4,842,869 to Forino, 4,948,598 to Lembke et al., 4,981,700 to Sarashvili et al., 5,019,410 to Pors et al., 5,104,665 to Fleet et al., and 5,413,925 to Lemonnier.